x64, x2apic/intr-remap: add x2apic support, including enabling interrupt-remapping
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / cpu / common_64.c
1 #include <linux/init.h>
2 #include <linux/kernel.h>
3 #include <linux/sched.h>
4 #include <linux/string.h>
5 #include <linux/bootmem.h>
6 #include <linux/bitops.h>
7 #include <linux/module.h>
8 #include <linux/kgdb.h>
9 #include <linux/topology.h>
10 #include <linux/string.h>
11 #include <linux/delay.h>
12 #include <linux/smp.h>
13 #include <linux/module.h>
14 #include <linux/percpu.h>
15 #include <asm/processor.h>
16 #include <asm/i387.h>
17 #include <asm/msr.h>
18 #include <asm/io.h>
19 #include <asm/mmu_context.h>
20 #include <asm/mtrr.h>
21 #include <asm/mce.h>
22 #include <asm/pat.h>
23 #include <asm/numa.h>
24 #ifdef CONFIG_X86_LOCAL_APIC
25 #include <asm/mpspec.h>
26 #include <asm/apic.h>
27 #include <mach_apic.h>
28 #endif
29 #include <asm/pda.h>
30 #include <asm/pgtable.h>
31 #include <asm/processor.h>
32 #include <asm/desc.h>
33 #include <asm/atomic.h>
34 #include <asm/proto.h>
35 #include <asm/sections.h>
36 #include <asm/setup.h>
37 #include <asm/genapic.h>
38
39 #include "cpu.h"
40
41 /* We need valid kernel segments for data and code in long mode too
42 * IRET will check the segment types kkeil 2000/10/28
43 * Also sysret mandates a special GDT layout
44 */
45 /* The TLS descriptors are currently at a different place compared to i386.
46 Hopefully nobody expects them at a fixed place (Wine?) */
47 DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
48 [GDT_ENTRY_KERNEL32_CS] = { { { 0x0000ffff, 0x00cf9b00 } } },
49 [GDT_ENTRY_KERNEL_CS] = { { { 0x0000ffff, 0x00af9b00 } } },
50 [GDT_ENTRY_KERNEL_DS] = { { { 0x0000ffff, 0x00cf9300 } } },
51 [GDT_ENTRY_DEFAULT_USER32_CS] = { { { 0x0000ffff, 0x00cffb00 } } },
52 [GDT_ENTRY_DEFAULT_USER_DS] = { { { 0x0000ffff, 0x00cff300 } } },
53 [GDT_ENTRY_DEFAULT_USER_CS] = { { { 0x0000ffff, 0x00affb00 } } },
54 } };
55 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
56
57 __u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
58
59 /* Current gdt points %fs at the "master" per-cpu area: after this,
60 * it's on the real one. */
61 void switch_to_new_gdt(void)
62 {
63 struct desc_ptr gdt_descr;
64
65 gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
66 gdt_descr.size = GDT_SIZE - 1;
67 load_gdt(&gdt_descr);
68 }
69
70 struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
71
72 static void __cpuinit default_init(struct cpuinfo_x86 *c)
73 {
74 display_cacheinfo(c);
75 }
76
77 static struct cpu_dev __cpuinitdata default_cpu = {
78 .c_init = default_init,
79 .c_vendor = "Unknown",
80 };
81 static struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
82
83 int __cpuinit get_model_name(struct cpuinfo_x86 *c)
84 {
85 unsigned int *v;
86
87 if (c->extended_cpuid_level < 0x80000004)
88 return 0;
89
90 v = (unsigned int *) c->x86_model_id;
91 cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
92 cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
93 cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
94 c->x86_model_id[48] = 0;
95 return 1;
96 }
97
98
99 void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c)
100 {
101 unsigned int n, dummy, eax, ebx, ecx, edx;
102
103 n = c->extended_cpuid_level;
104
105 if (n >= 0x80000005) {
106 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
107 printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), "
108 "D cache %dK (%d bytes/line)\n",
109 edx>>24, edx&0xFF, ecx>>24, ecx&0xFF);
110 c->x86_cache_size = (ecx>>24) + (edx>>24);
111 /* On K8 L1 TLB is inclusive, so don't count it */
112 c->x86_tlbsize = 0;
113 }
114
115 if (n >= 0x80000006) {
116 cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
117 ecx = cpuid_ecx(0x80000006);
118 c->x86_cache_size = ecx >> 16;
119 c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
120
121 printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n",
122 c->x86_cache_size, ecx & 0xFF);
123 }
124 if (n >= 0x80000008) {
125 cpuid(0x80000008, &eax, &dummy, &dummy, &dummy);
126 c->x86_virt_bits = (eax >> 8) & 0xff;
127 c->x86_phys_bits = eax & 0xff;
128 }
129 }
130
131 void __cpuinit detect_ht(struct cpuinfo_x86 *c)
132 {
133 #ifdef CONFIG_SMP
134 u32 eax, ebx, ecx, edx;
135 int index_msb, core_bits;
136
137 cpuid(1, &eax, &ebx, &ecx, &edx);
138
139
140 if (!cpu_has(c, X86_FEATURE_HT))
141 return;
142 if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
143 goto out;
144
145 smp_num_siblings = (ebx & 0xff0000) >> 16;
146
147 if (smp_num_siblings == 1) {
148 printk(KERN_INFO "CPU: Hyper-Threading is disabled\n");
149 } else if (smp_num_siblings > 1) {
150
151 if (smp_num_siblings > NR_CPUS) {
152 printk(KERN_WARNING "CPU: Unsupported number of "
153 "siblings %d", smp_num_siblings);
154 smp_num_siblings = 1;
155 return;
156 }
157
158 index_msb = get_count_order(smp_num_siblings);
159 c->phys_proc_id = phys_pkg_id(index_msb);
160
161 smp_num_siblings = smp_num_siblings / c->x86_max_cores;
162
163 index_msb = get_count_order(smp_num_siblings);
164
165 core_bits = get_count_order(c->x86_max_cores);
166
167 c->cpu_core_id = phys_pkg_id(index_msb) &
168 ((1 << core_bits) - 1);
169 }
170 out:
171 if ((c->x86_max_cores * smp_num_siblings) > 1) {
172 printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
173 c->phys_proc_id);
174 printk(KERN_INFO "CPU: Processor Core ID: %d\n",
175 c->cpu_core_id);
176 }
177
178 #endif
179 }
180
181 static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c)
182 {
183 char *v = c->x86_vendor_id;
184 int i;
185 static int printed;
186
187 for (i = 0; i < X86_VENDOR_NUM; i++) {
188 if (cpu_devs[i]) {
189 if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
190 (cpu_devs[i]->c_ident[1] &&
191 !strcmp(v, cpu_devs[i]->c_ident[1]))) {
192 c->x86_vendor = i;
193 this_cpu = cpu_devs[i];
194 return;
195 }
196 }
197 }
198 if (!printed) {
199 printed++;
200 printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n");
201 printk(KERN_ERR "CPU: Your system may be unstable.\n");
202 }
203 c->x86_vendor = X86_VENDOR_UNKNOWN;
204 }
205
206 static void __init early_cpu_support_print(void)
207 {
208 int i,j;
209 struct cpu_dev *cpu_devx;
210
211 printk("KERNEL supported cpus:\n");
212 for (i = 0; i < X86_VENDOR_NUM; i++) {
213 cpu_devx = cpu_devs[i];
214 if (!cpu_devx)
215 continue;
216 for (j = 0; j < 2; j++) {
217 if (!cpu_devx->c_ident[j])
218 continue;
219 printk(" %s %s\n", cpu_devx->c_vendor,
220 cpu_devx->c_ident[j]);
221 }
222 }
223 }
224
225 static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c);
226
227 void __init early_cpu_init(void)
228 {
229 struct cpu_vendor_dev *cvdev;
230
231 for (cvdev = __x86cpuvendor_start ;
232 cvdev < __x86cpuvendor_end ;
233 cvdev++)
234 cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
235 early_cpu_support_print();
236 early_identify_cpu(&boot_cpu_data);
237 }
238
239 /* Do some early cpuid on the boot CPU to get some parameter that are
240 needed before check_bugs. Everything advanced is in identify_cpu
241 below. */
242 static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c)
243 {
244 u32 tfms, xlvl;
245
246 c->loops_per_jiffy = loops_per_jiffy;
247 c->x86_cache_size = -1;
248 c->x86_vendor = X86_VENDOR_UNKNOWN;
249 c->x86_model = c->x86_mask = 0; /* So far unknown... */
250 c->x86_vendor_id[0] = '\0'; /* Unset */
251 c->x86_model_id[0] = '\0'; /* Unset */
252 c->x86_clflush_size = 64;
253 c->x86_cache_alignment = c->x86_clflush_size;
254 c->x86_max_cores = 1;
255 c->x86_coreid_bits = 0;
256 c->extended_cpuid_level = 0;
257 memset(&c->x86_capability, 0, sizeof c->x86_capability);
258
259 /* Get vendor name */
260 cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
261 (unsigned int *)&c->x86_vendor_id[0],
262 (unsigned int *)&c->x86_vendor_id[8],
263 (unsigned int *)&c->x86_vendor_id[4]);
264
265 get_cpu_vendor(c);
266
267 /* Initialize the standard set of capabilities */
268 /* Note that the vendor-specific code below might override */
269
270 /* Intel-defined flags: level 0x00000001 */
271 if (c->cpuid_level >= 0x00000001) {
272 __u32 misc;
273 cpuid(0x00000001, &tfms, &misc, &c->x86_capability[4],
274 &c->x86_capability[0]);
275 c->x86 = (tfms >> 8) & 0xf;
276 c->x86_model = (tfms >> 4) & 0xf;
277 c->x86_mask = tfms & 0xf;
278 if (c->x86 == 0xf)
279 c->x86 += (tfms >> 20) & 0xff;
280 if (c->x86 >= 0x6)
281 c->x86_model += ((tfms >> 16) & 0xF) << 4;
282 if (test_cpu_cap(c, X86_FEATURE_CLFLSH))
283 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
284 } else {
285 /* Have CPUID level 0 only - unheard of */
286 c->x86 = 4;
287 }
288
289 c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xff;
290 #ifdef CONFIG_SMP
291 c->phys_proc_id = c->initial_apicid;
292 #endif
293 /* AMD-defined flags: level 0x80000001 */
294 xlvl = cpuid_eax(0x80000000);
295 c->extended_cpuid_level = xlvl;
296 if ((xlvl & 0xffff0000) == 0x80000000) {
297 if (xlvl >= 0x80000001) {
298 c->x86_capability[1] = cpuid_edx(0x80000001);
299 c->x86_capability[6] = cpuid_ecx(0x80000001);
300 }
301 if (xlvl >= 0x80000004)
302 get_model_name(c); /* Default name */
303 }
304
305 /* Transmeta-defined flags: level 0x80860001 */
306 xlvl = cpuid_eax(0x80860000);
307 if ((xlvl & 0xffff0000) == 0x80860000) {
308 /* Don't set x86_cpuid_level here for now to not confuse. */
309 if (xlvl >= 0x80860001)
310 c->x86_capability[2] = cpuid_edx(0x80860001);
311 }
312
313 c->extended_cpuid_level = cpuid_eax(0x80000000);
314 if (c->extended_cpuid_level >= 0x80000007)
315 c->x86_power = cpuid_edx(0x80000007);
316
317 /* Assume all 64-bit CPUs support 32-bit syscall */
318 set_cpu_cap(c, X86_FEATURE_SYSCALL32);
319
320 if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
321 cpu_devs[c->x86_vendor]->c_early_init)
322 cpu_devs[c->x86_vendor]->c_early_init(c);
323
324 validate_pat_support(c);
325
326 /* early_param could clear that, but recall get it set again */
327 if (disable_apic)
328 clear_cpu_cap(c, X86_FEATURE_APIC);
329 }
330
331 /*
332 * This does the hard work of actually picking apart the CPU stuff...
333 */
334 static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
335 {
336 int i;
337
338 early_identify_cpu(c);
339
340 init_scattered_cpuid_features(c);
341
342 c->apicid = phys_pkg_id(0);
343
344 /*
345 * Vendor-specific initialization. In this section we
346 * canonicalize the feature flags, meaning if there are
347 * features a certain CPU supports which CPUID doesn't
348 * tell us, CPUID claiming incorrect flags, or other bugs,
349 * we handle them here.
350 *
351 * At the end of this section, c->x86_capability better
352 * indicate the features this CPU genuinely supports!
353 */
354 if (this_cpu->c_init)
355 this_cpu->c_init(c);
356
357 detect_ht(c);
358
359 /*
360 * On SMP, boot_cpu_data holds the common feature set between
361 * all CPUs; so make sure that we indicate which features are
362 * common between the CPUs. The first time this routine gets
363 * executed, c == &boot_cpu_data.
364 */
365 if (c != &boot_cpu_data) {
366 /* AND the already accumulated flags with these */
367 for (i = 0; i < NCAPINTS; i++)
368 boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
369 }
370
371 /* Clear all flags overriden by options */
372 for (i = 0; i < NCAPINTS; i++)
373 c->x86_capability[i] &= ~cleared_cpu_caps[i];
374
375 #ifdef CONFIG_X86_MCE
376 mcheck_init(c);
377 #endif
378 select_idle_routine(c);
379
380 #ifdef CONFIG_NUMA
381 numa_add_cpu(smp_processor_id());
382 #endif
383
384 }
385
386 void __cpuinit identify_boot_cpu(void)
387 {
388 identify_cpu(&boot_cpu_data);
389 }
390
391 void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
392 {
393 BUG_ON(c == &boot_cpu_data);
394 identify_cpu(c);
395 mtrr_ap_init();
396 }
397
398 static __init int setup_noclflush(char *arg)
399 {
400 setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
401 return 1;
402 }
403 __setup("noclflush", setup_noclflush);
404
405 void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
406 {
407 if (c->x86_model_id[0])
408 printk(KERN_CONT "%s", c->x86_model_id);
409
410 if (c->x86_mask || c->cpuid_level >= 0)
411 printk(KERN_CONT " stepping %02x\n", c->x86_mask);
412 else
413 printk(KERN_CONT "\n");
414 }
415
416 static __init int setup_disablecpuid(char *arg)
417 {
418 int bit;
419 if (get_option(&arg, &bit) && bit < NCAPINTS*32)
420 setup_clear_cpu_cap(bit);
421 else
422 return 0;
423 return 1;
424 }
425 __setup("clearcpuid=", setup_disablecpuid);
426
427 cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;
428
429 struct x8664_pda **_cpu_pda __read_mostly;
430 EXPORT_SYMBOL(_cpu_pda);
431
432 struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
433
434 char boot_cpu_stack[IRQSTACKSIZE] __page_aligned_bss;
435
436 unsigned long __supported_pte_mask __read_mostly = ~0UL;
437 EXPORT_SYMBOL_GPL(__supported_pte_mask);
438
439 static int do_not_nx __cpuinitdata;
440
441 /* noexec=on|off
442 Control non executable mappings for 64bit processes.
443
444 on Enable(default)
445 off Disable
446 */
447 static int __init nonx_setup(char *str)
448 {
449 if (!str)
450 return -EINVAL;
451 if (!strncmp(str, "on", 2)) {
452 __supported_pte_mask |= _PAGE_NX;
453 do_not_nx = 0;
454 } else if (!strncmp(str, "off", 3)) {
455 do_not_nx = 1;
456 __supported_pte_mask &= ~_PAGE_NX;
457 }
458 return 0;
459 }
460 early_param("noexec", nonx_setup);
461
462 int force_personality32;
463
464 /* noexec32=on|off
465 Control non executable heap for 32bit processes.
466 To control the stack too use noexec=off
467
468 on PROT_READ does not imply PROT_EXEC for 32bit processes (default)
469 off PROT_READ implies PROT_EXEC
470 */
471 static int __init nonx32_setup(char *str)
472 {
473 if (!strcmp(str, "on"))
474 force_personality32 &= ~READ_IMPLIES_EXEC;
475 else if (!strcmp(str, "off"))
476 force_personality32 |= READ_IMPLIES_EXEC;
477 return 1;
478 }
479 __setup("noexec32=", nonx32_setup);
480
481 void pda_init(int cpu)
482 {
483 struct x8664_pda *pda = cpu_pda(cpu);
484
485 /* Setup up data that may be needed in __get_free_pages early */
486 loadsegment(fs, 0);
487 loadsegment(gs, 0);
488 /* Memory clobbers used to order PDA accessed */
489 mb();
490 wrmsrl(MSR_GS_BASE, pda);
491 mb();
492
493 pda->cpunumber = cpu;
494 pda->irqcount = -1;
495 pda->kernelstack = (unsigned long)stack_thread_info() -
496 PDA_STACKOFFSET + THREAD_SIZE;
497 pda->active_mm = &init_mm;
498 pda->mmu_state = 0;
499
500 if (cpu == 0) {
501 /* others are initialized in smpboot.c */
502 pda->pcurrent = &init_task;
503 pda->irqstackptr = boot_cpu_stack;
504 } else {
505 pda->irqstackptr = (char *)
506 __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
507 if (!pda->irqstackptr)
508 panic("cannot allocate irqstack for cpu %d", cpu);
509
510 if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
511 pda->nodenumber = cpu_to_node(cpu);
512 }
513
514 pda->irqstackptr += IRQSTACKSIZE-64;
515 }
516
517 char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ +
518 DEBUG_STKSZ]
519 __attribute__((section(".bss.page_aligned")));
520
521 extern asmlinkage void ignore_sysret(void);
522
523 /* May not be marked __init: used by software suspend */
524 void syscall_init(void)
525 {
526 /*
527 * LSTAR and STAR live in a bit strange symbiosis.
528 * They both write to the same internal register. STAR allows to
529 * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
530 */
531 wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32);
532 wrmsrl(MSR_LSTAR, system_call);
533 wrmsrl(MSR_CSTAR, ignore_sysret);
534
535 #ifdef CONFIG_IA32_EMULATION
536 syscall32_cpu_init();
537 #endif
538
539 /* Flags to clear on syscall */
540 wrmsrl(MSR_SYSCALL_MASK,
541 X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL);
542 }
543
544 void __cpuinit check_efer(void)
545 {
546 unsigned long efer;
547
548 rdmsrl(MSR_EFER, efer);
549 if (!(efer & EFER_NX) || do_not_nx)
550 __supported_pte_mask &= ~_PAGE_NX;
551 }
552
553 unsigned long kernel_eflags;
554
555 /*
556 * Copies of the original ist values from the tss are only accessed during
557 * debugging, no special alignment required.
558 */
559 DEFINE_PER_CPU(struct orig_ist, orig_ist);
560
561 /*
562 * cpu_init() initializes state that is per-CPU. Some data is already
563 * initialized (naturally) in the bootstrap process, such as the GDT
564 * and IDT. We reload them nevertheless, this function acts as a
565 * 'CPU state barrier', nothing should get across.
566 * A lot of state is already set up in PDA init.
567 */
568 void __cpuinit cpu_init(void)
569 {
570 int cpu = stack_smp_processor_id();
571 struct tss_struct *t = &per_cpu(init_tss, cpu);
572 struct orig_ist *orig_ist = &per_cpu(orig_ist, cpu);
573 unsigned long v;
574 char *estacks = NULL;
575 struct task_struct *me;
576 int i;
577
578 /* CPU 0 is initialised in head64.c */
579 if (cpu != 0)
580 pda_init(cpu);
581 else
582 estacks = boot_exception_stacks;
583
584 me = current;
585
586 if (cpu_test_and_set(cpu, cpu_initialized))
587 panic("CPU#%d already initialized!\n", cpu);
588
589 printk(KERN_INFO "Initializing CPU#%d\n", cpu);
590
591 clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
592
593 /*
594 * Initialize the per-CPU GDT with the boot GDT,
595 * and set up the GDT descriptor:
596 */
597
598 switch_to_new_gdt();
599 load_idt((const struct desc_ptr *)&idt_descr);
600
601 memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
602 syscall_init();
603
604 wrmsrl(MSR_FS_BASE, 0);
605 wrmsrl(MSR_KERNEL_GS_BASE, 0);
606 barrier();
607
608 check_efer();
609 if (cpu != 0 && x2apic)
610 enable_x2apic();
611
612 /*
613 * set up and load the per-CPU TSS
614 */
615 for (v = 0; v < N_EXCEPTION_STACKS; v++) {
616 static const unsigned int order[N_EXCEPTION_STACKS] = {
617 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
618 [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
619 };
620 if (cpu) {
621 estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
622 if (!estacks)
623 panic("Cannot allocate exception stack %ld %d\n",
624 v, cpu);
625 }
626 estacks += PAGE_SIZE << order[v];
627 orig_ist->ist[v] = t->x86_tss.ist[v] = (unsigned long)estacks;
628 }
629
630 t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
631 /*
632 * <= is required because the CPU will access up to
633 * 8 bits beyond the end of the IO permission bitmap.
634 */
635 for (i = 0; i <= IO_BITMAP_LONGS; i++)
636 t->io_bitmap[i] = ~0UL;
637
638 atomic_inc(&init_mm.mm_count);
639 me->active_mm = &init_mm;
640 if (me->mm)
641 BUG();
642 enter_lazy_tlb(&init_mm, me);
643
644 load_sp0(t, &current->thread);
645 set_tss_desc(cpu, t);
646 load_TR_desc();
647 load_LDT(&init_mm.context);
648
649 #ifdef CONFIG_KGDB
650 /*
651 * If the kgdb is connected no debug regs should be altered. This
652 * is only applicable when KGDB and a KGDB I/O module are built
653 * into the kernel and you are using early debugging with
654 * kgdbwait. KGDB will control the kernel HW breakpoint registers.
655 */
656 if (kgdb_connected && arch_kgdb_ops.correct_hw_break)
657 arch_kgdb_ops.correct_hw_break();
658 else {
659 #endif
660 /*
661 * Clear all 6 debug registers:
662 */
663
664 set_debugreg(0UL, 0);
665 set_debugreg(0UL, 1);
666 set_debugreg(0UL, 2);
667 set_debugreg(0UL, 3);
668 set_debugreg(0UL, 6);
669 set_debugreg(0UL, 7);
670 #ifdef CONFIG_KGDB
671 /* If the kgdb is connected no debug regs should be altered. */
672 }
673 #endif
674
675 fpu_init();
676
677 raw_local_save_flags(kernel_eflags);
678
679 if (is_uv_system())
680 uv_cpu_init();
681 }